Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.Concept Reference Code: B94KAR01HQUSName Used in Concept Reference: Arabis macdonaldianaTaxonomic Comments: Kartesz (1994 checklist and 1999 Synthesis) spells this name 'macdonaldiana'. Flora of North America (vol. 7, 2010) and the International Plant Name Index (as of April 18, 2011) spell it 'mcdonaldiana.' In the original Federal Register notice listing this species as endangered, the USFWS spelled the epithet 'macdonaldiana.' However, in the October 31, 1995, special reprint of the list of Endangered and Threatened Wildlife and Plants, the epithet was spelled 'mcdonaldiana'; as of May, 1999, this spelling was still used in USFWS documents, along with the common name "McDonald's rock-cress" (e.g., species list on USFWS web site, accessed 21May1999). As of the March 25, 2009 Federal Register initiation of 5 year review, USFWS spells the epithet 'macdonaldiana' with the common name still McDonald's rock-cress. Although the 1978 USFWS listing notice did not specifically address taxonomy, it is presumed that the treatment used by USFWS did not include A. serpentinicola, since A. serpentinicola was given a category 2 candidate status in 1993, independently of previously listed A. macdonaldiana.

Conservation Status

NatureServe Status

Global Status: G3Global Status Last Reviewed: 14Dec2015Global Status Last Changed: 14Dec2015Ranking Methodology Used: Ranked by calculatorRounded Global Status: G3 - VulnerableReasons: Restricted to serpentine areas and known from 30-40 sites in northern California (Mendocino, Del Norte and Siskiyou counties) and immediately adjacent southwestern Oregon. Some populations are threatened by mining of the nickel-rich soils of its habitat and encroachment of woody vegetation. Many sites are on USFS lands, but none may be in permanent protection.Nation: United StatesNational Status: N3

U.S. & Canada State/Province StatusDue to latency between updates made in state, provincial or other
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for state or provincial information you may wish to contact the data steward
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United States

California (S3), Oregon (S1)

Other Statuses

U.S. Endangered Species Act (USESA): LE: Listed endangered(28Sep1978)Comments on USESA: Arabis macdonaldiana was proposed endangered on June 16, 1976 and determined endangered on September 28, 1978.U.S. Fish & Wildlife Service Lead Region: R8 - California-Nevada

NatureServe Global Conservation Status Factors

Range Extent Comments: Occurs in the Siskiyou mountains of Curry and Josephine counties, Oregon. In California, the species is reported from Del Norte, Mendocino, Siskiyou, and Trinity counties.

Area of Occupancy: 26-125 4-km2 grid cellsArea of Occupancy Comments:

Number of Occurrences: 21 - 80Number of Occurrences Comments: California has 29 occurrences, 4 of which are historic. Oregon has 10 occurrences but one is historic.

Population Size Comments: The total number of known plants is about 17,500.

Number of Occurrences with Good Viability/Integrity: Some (13-40)

Overall Threat Impact: Very high - mediumOverall Threat Impact Comments: Mining is the greatest threat (CNPS 2001, CNDDB 2003). The California Natural Diversity Database reports that grazing was observed at one occurrence (2003). This situation was unchanged in January 2006. Lack of fire, which leads to competition from woody vegetation, is a threat.

Short-term Trend: Decline of 10-30%Short-term Trend Comments: The short term trend is estimated to be slightly declining due to mining activities.

Long-term Trend: Decline of 30-50%Long-term Trend Comments: The long term trend is estimated to be declining due to mining activities.

Environmental Specificity: Narrow. Specialist or community with key requirements common. Environmental Specificity Comments: Known from 2 or 3 specific areas on serpentine on the north coast of California and in Oregon.

Other NatureServe Conservation Status Information

Distribution

Global Range:
Occurs in the Siskiyou mountains of Curry and Josephine counties, Oregon. In California, the species is reported from Del Norte, Mendocino, Siskiyou, and Trinity counties.

U.S. States and Canadian Provinces

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Please refer to our Distribution Data Sources to find
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Available http://explorer.natureserve.org. (Accessed:

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